I am not sure I can qualify this as an answer, but you sound like a man from your question, so let me comment on 2 of your non-missing elements:
Made arrangements for who will catch and cut the umbilical cord
Well, it won't be her! If it is her, then this is far from your first child.
Have discussed what levels of pain medications to use
Such a nice thought to have, isn't it? Yeah, well, life might not care so much when the birth gets a goin' -- remember that it is her giving birth, not you, so if she changes her mind, let her. You really don't want her to be in a mood to show you why you should have given in later on!
Now... I planned, planned, planned... the Midwife, all the Nurses, and even the backup Doctor had printed copies of instructions. I had everything planned! Random umbilical cord around the neck -- oh, yeah: prepared!
Reality didn't seem to care about my confidence level. Suddenly it was taking too long, the umbilical cord was wrapped around the neck, she got stuck mid-way, they needed to monitor her pulse by putting a thing into her head before she was out, the first one was a dud and had to do it again... and I had to make all the decisions on the fly!
Yeah... going to all the classes, reading 4 or 5 books on birth, and everything else I could imagine just did not have me fully ready for reality.
That said, I had the one thing that was my "fail safe": her mother and I had agreed on the general principles. My decisions reflected her decisions. And where her input was needed, I deferred to her (the baby wasn't coming out of me!)
Add to your list (as the guy who isn't healing) that the baby NEVER LEAVES YOUR PRESENCE!
When you go and s/he gets shots, feet printed, etc. and you notice very few, if any, other parents there and know that your child has a caring parent there, you'll appreciate it so much!
I hope that helps, but still not sure that this 100% qualifies as an answer.
(Oh, and congrats on your first! It's truly the most stressful.)